liebermann etal



Sept. 10, 1963 J. LIEBERMANN ET AL 3,103,567

PRESSURE ACTUATED SWITCH DEVICE 3 Sheets-Sheet 1 Filed Jan. l0, 1961 ATTORNEY Sept. 10, 1963 J. LIEBERMANN ETAL 3,103,567

PRESSURE ACTUATED SWITCH DEVICE 3 Sheets-Sheet 2 Filed Jan. lO, 1961 a Il INVENTORS '4 Fi 4 JOHN LIEBERMANN g- WILLIAM H. cRoswELL THOMAS I. sYFERr 6 ATT NEE Sept. 10, 1963 J. Lu-:BERMANN ET AL 3,103,567

PRESSURE ACTUATED SWITCH DEVICE 5 Sheets-Sheet 5 Filed Jan. l0, 1961 ATTORN United States Patent O 3,103,567 PRESSURE ACTUA'IED SWITCH DEVICE llohn Liebermann, William H. Croswell, and Thomas I.

Syfert, Columbus, Ohio, assigrxors to Ranco Incorporated, Columbus, Ohio, a corporation of Ohio Filed Jan. 10, 1961, Ser. No. 81,764 1 Claim. (Cl. 26d-140) This invention relates to pressure actuated control devices, and more particularly to an improved control device of the type including an electric switch actuated b-y a pressure responsive power element such as an expansible bellows, and which is adjustable to vary the pressure responsive characteristics of the device.

Control devices or switches of the above mentioned character, in which the bellows forms part of a thermally responsive means, are often used in refrigerators, ai-r conditioners and the like apparatus wherein a compressor motor is energized in cycles governed by the temperature iiuctuations of an evaporator or of the medium being cooled. kBecause of the ever-present desire to conserve space in refrigerators, for example, the controls thereof are often located between the spaced surfaces of an insulated wall with a rotatable control shaft extending through one of the surfaces. Recent advances in insulating materials and techniques, however, have substantially reduced the available space between the surfaces of such wall-s in which the control device may be accommodated.

Accordingly, it -is one object of the present invention .to provide an improved control device having a bellows operated switch and a rotatable controlV shaft for adjusting the operating characteristics of the y switch, and which device is compact and of such a configuration that it may be conveniently mounted between relatively closely spaced surfaces. v

Another object of thisinvention is to provide an improved thermost'atic'switch device having a generally rectangular configuration with a control shaft extending from one side thereof and having terminals for making electrical connections therewith disposed on a 4side normal to the side from which the shaft extends, and having a tubular element extending from another side which is also normal to the side :from which the .shaft extends, whereby the housk ing has a relatively shallow dimension in a direction axially of said shaft so that the device may 'be installed between two parallel surfaces or panels with the control .shaft extending through an opening in one panel and with the terminal-s and tubular element free from inter-ference with either of the panels. l i

Still another object of this invention is the provision of a thermostatically operated snap-acting switch mechanism, disposed in housing means including wall portions of insulating material, and comprising an elongated rigid conductor member attached to one wall of the housing so that one end portion of the conductor member provides a bracket or support 'for -a movable contact arm of the switch While the other end portion projects through a wall of the housing to' provide terminal connector for the switch.

Yet another object of the invention -is the provision of a thermostatcally operated switching mechanism comprising a rectangular housing formed in part of insulating material, the housing having -a recess delined in one end, and a part of terminal members projecting into the recess, one of which members extends from within the housing where it forms a support ltor the movable contact of the switch mechanism, and the other of which forms a support for a relatively xed contact of the switching mechanism.

The invention may be further described as residing in certain novel constructions and arrangements of parts and other objects and advantages thereof will become apparent from the following description of a preferred torm of the ICC invention and from the accompanying sheets of drawings, forming a part of this specilication, and in which- FIG. l is a perspective view of a control device embody ing the presentinvention;

FIG. 2 is a sectional view of the device of FIG. 1 taken along line 2-2 thereof and on an enlarged scale;

FIG. 3 is a sectional view of the device taken substantially along line 3--3` of FIG. 2;

FIG. 4 is a sectional view taken substantially along line 4-4 of FIG. 2; and

FIG. 5 is a sectional View taken along line S-S of FIG. 4.

Although pressure actuated control means embodying this invention may be actuated by other pressure means and may be used for other purposes, the form of the invention illustrated in the drawings and described hereinafter comprises a generally rectangular electric control switch operated by a thermally responsive bellows means and is particularly useful in controlling the cyclic operation of domestic refrigerators, conditioning apparatus, and the like. Referring now to the drawings, there is illustrated therein a generally rectangular switch device 1t)l which includes a channel shaped housing member 1-1, preferably formed of sheet metal and including parallel side walls 11u and 11b joined by a top wall 11e. A mounting plate i 12 is disposed in spaced relation with, and overlying top wall 11e, and is secured thereto by lugs =1 1d crimped thereover.

An insulating member 14, preferably molded `front a suitable material, such as Bakelite, or other plastic, is secured between the side ywalls 11a, l11b by laterally extending lugs 14a received in Icorresponding openings in the side walls, the latter being crimped adjacent those openings as indicated at 11e, to secu-re the insulator member 'against movement. Channel member 11 and insulator member 14 together form a housing for the snap switch mechanism which will be more fully described hereafter. The insulator member `14 comprises a bottom 'Wall portion 14h and an oliset or enlarged end portion 14C 4which forms one end wall of the housing and has a pair of recesses 14d and 114e delined therein. Within the housing formed by channel member `11 and insulator member 14 there is contained a snap acting switch mechanism, one component of which comprises an elongated relatively rigid electrical conductor vl5 having a relatively straight portion :15a recessed in the inner surface of insulator wall 14h and secured thereto as by a rivet 16. Conductor 15 includes a U-shaped or offset portion 15b which extends through anopening 17 in the wall 14b of the housing formed by insulator member 14 and presents a blade type terminal connector 15e in recess 14d. Offset portion 15b and terminal connector 15C are conveniently secured against movement by a rivet 18 extending through insulator end portion 14C.

The inner end of conductor i1'5 terminates in an upturned leg 15d to which one end of a movable switch arm 2.0 is fastened by a rivet 2d so that the conductor provides a bracket or support for this arm. Switch arm 20, which is preferably formed of flat spring metal, such as beryllium copper, and has an elongated central opening 20u defined therein, is provided at its other end with an electrical contact 20b. A stationary contact support member 22 has a stationary contact 22athereon which is in registry with Contact 20]?. Member Z2 lextends through, and is fixed in, an opening in insulator end portion 14C and presents a blade type terminal connector 22h in recess 14e. The recesses 14d, 14e with the terminal connectors projecting therein provide socket means for the reception of wiring terminal connectors. It will be understood that although Itwo recesses 14d and 14e are shown, these may be combined into a single larger recess.

vsion of spring 26 acting through toggle bar 25.

Any suitable means may be provide-d for effecting snap acting movement of switch arm 20 to bring contact 2017 thereof into and out of engagement with contact 22a for Inaking and beraking an electric circuit therethrough, and in the embodiment shown comprises "a toggle bar 25, having notched ends 25a and 25h, which is disposed in opening 20a and has the end 25a thereof in pivotal engagement with arm #2.0 adjacent the free end thereof. A fi-shaped toggle spring 26 is disposed in opening 20a and has one end pivotally engaging the notched end 25b of toggle bar 25, and has its other end in pivot-a1 engagement with arm 20l adjacent the fixed end thereof.

' A lswitch operating member in the form. of a spring arm-28 has a downturned portion 28a at one end thereof secured to conductor leg 15d by rivet 21, and is disposed in overlying relation to switch arm 20. Spring arm 28 has an elongated central opening 23h in partial registration with opening 20a of the switch arm, and includes a depending member 28C struck out therefrom. Toggle bar Z extends through a slot in depending member 28e and is adapted to be moved thereby for operation of the switch. Spring arm 28 lis normally biased, by the spring action thereof, away from insulator member 14 toward lthe positionillustrated in FIG. 2, in which posi-tion the contacts 2Gb, 22a are held open by the ten- The extent to which contacts 2Gb, 22a may open is limited by a screw 30 extending througha threaded opening in conductor member 15 and which screw is adapted to be engaged by toggle bar 25. Screw 30 may be referred to as a diiferential adjusting screw since the adjustment thereof controls the difference between the cut out and cut inY temperatures at which the switch operates. Upon movement of spring member 28 toward insulator member 14 by means which will presently be described, toggle har l25 is pivoted about the end 25a thereof and, as the pivotal connection between spring 2-6 and `end 215]) of bar Z5 passes through the plane of switch arm 20, the toggle spring 26 will act through toggle bar 25 to bring contacts 2Gb, 22a together with a snap movement.

. Anractuating lever 32, comprising an arm 32a having an upturned end portion 32h and including a pair of spaced bearing portions .326, is pivoted to the housing by -a pivot pin 34 extending through side walls 11a, 11b

and through the bearing portions. Arm 32a overlies switch spring 23, and an insulating member y35 is disposed therebetween and is secured to lever arm 32a lfor movelment with the latter by tabs 32e which lare crimped around the insulating member. Lever arm 32a has a raised centralportion terminating in a free end 32d `which is adapted to be acted upon by a thermally responsive expansible bellows 36. In this instance, bellows 36 comprises an annular bellows portion having an axially extending post 36a inengagement with the lever portion 32d. The bellows 36 is mounted on a plate 37 which is received between the side walls llla, 11b and forms one end wall of the switch device A tubular element 38 is secured at one end to plate 37 Iand communicates with the interior of bellows 36. Fllnbular element 38 is sealed at its other end and the tubular element, and bellows 36 contain a iiuid which expands and contracts with increases and decreases in temperature. Changes in temperature experienced by the tubular element 38 therefore result in axial expansion and contraction of bellows 36 with/axial movement of the bellows post 36a being transmitted through lever arm 32a and insulator 35 thereof, to switch spring 28 so as to effect actuation of the snap switch mechanism.

Adjustable loading means are provided for varying the temperature range in which the switch mechanism will be operated` by bellows 36, 'and comprise a lever 40 having spaced bearing portions 40a supported coaxially with bearing portions 32C of lever 32 on pin 34. An extension spr-ing 42 has one end 42a thereof connected to lever 40 and has the other end thereof connected by ian adjusting screw 43 to end portion 32b of lever 32. Screw 43 is threadedly engaged in a member 41 which is lodged in the convolutions of spring 4t2, and the head 43a of the screw |is provided with a screwdriver slot @3b for rotating the screw to increase or decrease the tension of spring 42. A bent wire spring 44, having one portion extending through an opening in lever end 32h, has la leg 44a engaged in an annular groove formed in screw head 43a. Spring 44 serves to prevent rotation of screw 43- under the inlluence of vibration or the like. A removable access cover 45 having resilient tongues 45a, is located between side walls 11a, 1lb, and between top wall y11c and end portion 14C of insulator member 14. Cover 45 may be conveniently removed to provide access to the adjusting screw 43.

A rotatable cam 47 is disposed against the under side of wall `11C and is secured to a shaft 48 rotatably journaled in that wall for rotation therewith.k Cam 47 has a cam surface y47a engaged by cam follower portion 401:

' of llever 4d and serves to Iadjustably p-osition lever 40 to increase or decrease the tension of spring 4Z Aand thereby vary the loading force on bellows 36 to vary the temperature at which the switch mechanism wil-l be operated. Shaft #t8 may, of course, beprovided with a suitable knob 49 for rotating cam 47, and knob 49 may cooperate with indicia on a suit-able panel for aiding in setting the switch.

In some instances it is desirable to be able to place the switch in an inoperative condition so that it will not respond to temperature changes, such as when a refrigerator is desired to be placed in an off condition. For

this purpose lever di! is provided with an arm 4910 which is adapted, upon movement of cam 47 to bring the highest Y point Wb-thereof to bear on cam follower itlb, to engage lever l32 and prevent movement thereof regardless Vof pressure changes within the bellows 36.

It will be observed that conductor 15 provides the support for switch arm 20, the toggle means 25 and 26, the switch operating spring 28, and the differential adjusting screw 30. By means of this construction there is provided a particularly compact, inexpensive, and reliable switch mechanism which is capable of repeatedly being Operated with a minimum of wear and change of operating characteristics. It will also be observed that by having the tubular element y38 of the thermally responsive power element extending from one end of the device, while the terminal means 15C land 22b are located at the other end of the device, the dimension thereof axially of shaft 48 is maintained at a minimum, thereby permitting the device to `be installed between closely spaced panels without interference with the element 38 and the wiring. Moreover, the terminals 15e and 2212 are completely recessed within the end portion 14C of insulator member 14. `A cover 50` of flexible insulating material, such as Teflon or the like, is provided to protect the conductor 15 and rivet 16 against coming into contact with a panel formed of conductive material.

From the foregoing detailed description of a preferred form of control switch device embodying the present invention, and from the accompanying sheets of drawings, it will be appreciated that therehas been' provided thereby a particularly compact yet easily regulated vand adjusted control device which is adapted to be mounted in conned spaces such as in the insulated wall of a r'efnigerator or the like.

Having described our invention, We claim:

A pressure actuated switch device comprising an elongated housing structure including a side wall and .a relatively short end Wall both formed of insulating material and joined at right tangles to one another, said side wall having an opening therethrough adjacent to said end wall, an elongated relatively rigid rst conductor member attached to land extending along the inside of said side wall longitudinally of said housing and through said opening land having a portion turned :at right angles at the junction of said Wallls whereby a section thereof lies against the outside of said end wall, the outer end of said section being turned to project `from said end wall and normal thereto to form a blade type terminal, the opposite end of said conductor member having Ia second seotion turned inwardly from said side wall, means securing said conductor member to said side wall, a movable contact arm attached at one end to said second section of said rst conductor member andv extending generallly parallel to and in spaced relation to said first conductor member, said contact arm having a movable contact carried on the other end thereof, a second conductor member having one end extending through said end wall to form a terminal rspaced from 'and parallel to said outer end of the first mentioned section of said iirst conductor member, and having ,a fixed contact on the other end thereof engageable by said movable contact, an' expansible power element mounted on :a second end wall of said housing opposite the iirst mentioned end wa-ll, said power element having a portion movable towlard :and away from said lirst end wall, and having a capillary ftube extending outwardly of said second end wall, snap acting means connecting said power element and said cont-act arm and operative to open and close said contacts in' response vto movement of said power element, and a rotatable control member threaded in said first contact member through the portion thereof extending Ialong the inside of said side wal-l and engaging a part of said snap *acting means..

v References Cited in the file of this patent UNITED STATES PATENTS 2,403,824 Newell July 9, 1946 2,486,873 Pearce Nov. =l, 1949 2,647,190 Lieberman July 28, 1953 2,725,444 Grooms Nov. 29, 1955 2,727,956 Winter Dec. 20, 1955 2,754,071 Weber et a1. Aug. 14, |1956 2,784,272 Carter Mar. 5, 1957 2,795,674 Grimsl'taw June 11, 1957 

